Surface cleaning and modifying method and surface cleaning and modifying apparatus

ABSTRACT

A self-cleaning step for cleaning an elastic abrasive body  231  itself by pressing the rotating elastic abrasive body  231  against a pressing member  221  to deform the elastic body  231  while supplying slurry L containing abrasive to the elastic abrasive body  231  so as to clean the elastic abrasive body  231  is added to a scrub cleaning step in which a plastic optical component  1  is rotated and the rotating elastic abrasive body  231  is pressed against a surface of the plastic optical component  1  while supplying slurry L containing abrasive between the surface of the plastic optical component  1  and the elastic abrasive body  231  so as to clean the plastic optical component  1.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from Japanese Patent Application JP2003-384070 filed Nov. 13, 2003, which is incorporated by reference,herein, in its entirety.

FIELD OF THE INVENTION

The present invention relates to a surface cleaning and modifying methodand surface cleaning and modifying apparatus capable of effectivelycleaning a surface of a plastic optical component such as a plasticlens.

BACKGROUND OF THE INVENTION

A drawback to a plastic optical component is that it is easily scratcheddue to its softness. Thus, a hard-coating for providing anti-frictionand anti-scratch properties is formed on a surface of the plasticoptical component, and an anti-reflection coating is overlaid on thehard-coating, thereby improving the performance and function of theplastic optical component.

Particularly for a plastic spectacle lens, hard-coating formation is asurface treatment essential to improve the hardness of the lens surfaceand the tight connection with an evaporated coating and to providecolorability.

As a pretreatment for hard-coating formation, it is necessary to carryout a cleaning step for cleaning the surface of the plastic opticalcomponent so as to remove dust and dirt adhering thereto for theachievement of sufficient reaction between a hard-coating and amaterial. When cleaning in the cleaning step is insufficient, theappearance and durability of the surface of the plastic opticalcomponent are adversely affected, resulting in lowered yields. Thus, thecleaning step is an important pretreatment.

In a conventional method for cleaning the plastic optical component, thedirt adhering to the surface of the optical component is dissolved andseparated using a dip-type cleaning apparatus.

An improvement to the conventional cleaning method has been proposed inJP-A-5-70615 and in JP-A-11-48117. According to these proposals, a scrubcleaning method for polishing the surface of the optical component withabrasive is performed by supplying slurry, which contains abrasivedispersed in water, while scrubbing the surface of the optical componentwith an elastic abrasive body (or by scrubbing the surface of theoptical component with an elastic abrasive body, which contains abrasivedispersed therein, while pouring water).

This scrub cleaning method is a surface cleaning and modifying methodcapable of removing dirt adhering to the surface of the plastic opticalcomponent and a non-uniform surface formed due to degradation or othercaused during or after shaping by physically polishing the surface ofthe plastic optical component with abrasive. By this method, drawbacksin appearance such as cissing caused by dirt are prevented, andhard-coating is sufficiently tight-connected and bonded with the surfaceof the optical component without hindrance by a non-uniform layer,thereby enhancing the tight connection between the surface and thehard-coating. Additionally, the connection tightness is furtherincreased due to activation of the surface caused by polishing and ananchor effect caused by minute polishing scratches.

However, in the above-described scrub cleaning method, dirt orcontaminant sometimes remains on the elastic abrasive body aftercleaning the plastic optical component. If the next plastic opticalcomponent is cleaned with the elastic abrasive body to which dirt orcontaminant adheres, the dirt or contaminant may be transferred to thesurface of the plastic optical component or may scratch the surfacedeeply. Thus, the dirt, contaminant and deep scratches existing on thesurface of the plastic optical component have been the cause forlowering yields of the hard-coating formation treatment.

SUMMARY OF THE INVENTION

The present invention has been developed to solve the above-describedproblem. It is an object of the invention to provide a surface cleaningand modifying method and surface cleaning and modifying apparatuscapable of polishing and cleaning a plastic optical component withabrasive using an elastic abrasive body without leaving dirt or deepscratches on a surface of the plastic optical component.

In order to achieve the above object, a first aspect of the invention isto provide a surface cleaning and modifying method. This method providesfor scrub cleaning a plastic optical component, including rotating theplastic optical component, pressing a rotating elastic abrasive bodyagainst a surface of the plastic optical component, and, during thepressing, supplying a liquid between the surface of the plastic opticalcomponent and the elastic abrasive body, the liquid being a slurry withdispersed abrasive. This method also provides for self-cleaning of theelastic abrasive body, including deforming the elastic abrasive body,and during the deforming, supplying a liquid, to the elastic abrasivebody, the liquid being a slurry including dispersed abrasive.

The plastic optical component is scrub-cleaned with abrasive using theelastic abrasive body in the scrub cleaning step, and the elasticabrasive body itself used for the cleaning is cleaned to remove dirt orcontaminant adhering to the elastic abrasive body in the self-cleaningstep. The self-cleaning step prevents dirt or contaminant fromre-adhering to the plastic optical component from the elastic abrasivebody. In addition, the self-cleaning step prevents desiccation of theelastic abrasive body. As a result, the plastic optical component can becleaned without being deeply scratched by the dried elastic abrasivebody.

A second aspect of the invention is to provide the surface cleaning andmodifying method described in the first aspect of the invention, whereinsaid self-cleaning further comprises placing said elastic abrasive bodyand a pressing member in contact to deform said elastic abrasive body.

Since the elastic abrasive body is largely deformed by pressing thepressing member and the elastic abrasive body against each other, theelastic abrasive body can be effectively self-cleaned.

A third aspect of the invention is to provide the surface cleaning andmodifying method as in the first aspect of the invention, furthercomprising alternately performing said scrub cleaning and saidself-cleaning.

Since the scrub cleaning is performed using the elastic abrasive bodywhich is always cleaned by providing the self-cleaning step between thescrub cleaning steps, the plastic optical component can be cleanedwithout leaving dirt and large scratches thereon.

A fourth aspect of the invention is to provide a surface cleaning andmodifying method. In this method, there is a scrub cleaning a plasticoptical component, including rotating the plastic optical component,pressing a rotating elastic abrasive body against a surface of theplastic optical component, the elastic abrasive body including dispersedabrasive, and during the pressing, supplying a liquid including waterbetween the surface of said plastic optical component and said elasticabrasive body. This method also provides for the self-cleaning of theelastic abrasive body, including deforming the elastic abrasive body,and, during the deforming, supplying a liquid including water to theelastic abrasive body.

The plastic optical component is scrub-cleaned with abrasive using theelastic abrasive body in the scrub cleaning step, and the elasticabrasive body itself used for the cleaning is cleaned to remove dirt orcontaminant adhering to the elastic abrasive body in the self-cleaningstep. The self-cleaning step prevents dirt or contaminant fromre-adhering to the plastic optical component from the elastic abrasivebody. In addition, the self-cleaning step prevents desiccation of theelastic abrasive body. As a result, the plastic optical component can becleaned without being deeply scratched by the dried elastic abrasivebody.

A fifth aspect of the present invention is to provide the surfacecleaning and modifying method as described in the fourth aspect of theinvention, wherein the self-cleaning further includes placing theelastic abrasive body and a pressing member in contact to deform theelastic abrasive body.

Since the elastic abrasive body is largely deformed by pressing thepressing member and the elastic abrasive body against each other, theelastic abrasive body can be effectively self-cleaned.

A sixth aspect of the invention is to provide the surface cleaning andmodifying method as described in the fourth aspect of the invention,further including alternately performing the scrub cleaning and theself-cleaning.

Since the scrub cleaning is performed using the elastic abrasive bodywhich is always cleaned by providing the self-cleaning step between thescrub cleaning steps, the plastic optical component can be cleanedwithout leaving dirt and large scratches thereon.

A seventh aspect of the invention is to provide a surface cleaning andmodifying apparatus. This apparatus includes an optical component holderholding and rotating a plastic optical component, a pressing memberseparate from said optical component holder, an abrasive body holderholding and rotating an elastic abrasive body, an operation sectionoperating one or more of the optical component holder and the abrasivebody holder so as to perform operations. The operations include acleaning action of pressing the elastic abrasive body against theplastic optical component, and a self-cleaning action of placing theelastic abrasive body in contact with the pressing member. Thisapparatus also includes a liquid supply member for supplying liquid tothe elastic abrasive body during the cleaning action and theself-cleaning action.

In the scrub cleaning step, the elastic abrasive body is held androtated by the abrasive body holder with the plastic optical componentheld and rotated by the optical component holder. In this condition, theelastic abrasive body is pressed against the surface of the plasticoptical component by the operation section while supplying liquid fromthe liquid supply member to conduct the scrub cleaning. In theself-cleaning step, the elastic abrasive body rotated by the abrasivebody holder is pressed against the pressing member by the operationsection while supplying liquid from the liquid supply member to conductthe self-cleaning.

An eighth aspect of the invention is to provide the surface cleaning andmodifying apparatus as described in the seventh aspect of the invention,wherein the operation section conducts the cleaning action and theself-cleaning action alternately.

Since the scrub cleaning is performed using the elastic abrasive bodywhich is always cleaned by providing the self-cleaning step between thescrub cleaning steps, the plastic optical component can be cleanedwithout leaving dirt and large scratches thereon.

A ninth aspect of the invention is to provide the surface cleaning andmodifying apparatus as described in the seventh aspect of the invention,wherein the liquid is a slurry that includes dispersed abrasive.

The surface of the plastic optical component is polished and modifiedwith abrasive by supplying slurry which contains abrasive dispersed inliquid to the surface of the plastic optical component.

A tenth aspect of the invention is to provide the surface cleaning andmodifying apparatus as described in the seventh aspect of the invention,in which the elastic abrasive body includes dispersed abrasive.

And an eleventh aspect of the invention is to provide the surfacecleaning and modifying apparatus as described in the tenth aspect of theinvention, such that the liquid includes water.

The surface of the plastic optical component is cleaned and modifiedwith abrasive by polishing the surface using the elastic abrasive bodywhich contains abrasive dispersed therein while supplying water. Theelastic abrasive body is cleaned with water while being pressed againstthe pressing member, thereby removing dirt and contaminant adhering tothe elastic abrasive body itself.

A surface cleaning and modifying method and surface cleaning andmodifying apparatus of the present invention are utilized for cleaning asurface of a plastic optical component such as a plastic lens, and forpretreatment before forming a hard-coating or other.

The invention is taught below by way of various specific exemplaryembodiments explained in detail, and illustrated in the enclosed drawingfigures.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawing figures depict, in highly simplified schematic form,embodiments reflecting the principles of the invention. Many items anddetails that will be readily understood by one familiar with this fieldhave been omitted so as to avoid obscuring the invention. In thedrawings:

FIG. 1(a) is a flowchart of manufacturing steps in which cleaning andhard-coating formation are carried out first on one side of a plasticlens and subsequently on the other side.

FIG. 1(b) is a flowchart of manufacturing steps in which both sides ofthe plastic lens are cleaned and subsequently coated with hard-coatingsat a time.

FIG. 2 illustrates arrangements of lens cleaning equipment in a firstembodiment.

FIG. 3 schematically illustrates a structure of surface cleaning andmodifying apparatus in the first embodiment.

FIG. 4 schematically illustrates a structure of a self-cleaning device.

FIG. 5 illustrates a disposition of a lens cleaning device in a secondembodiment.

FIGS. 6(a), 6(b), and 6(c) schematically illustrate a structure ofsurface cleaning and modifying apparatus in the second embodiment. Inparticular: FIG. 6(a) shows a condition before cleaning starts; FIG.6(b) shows a condition during scrub cleaning; and FIG. 6(c) shows acondition during self-cleaning.

DETAILED DESCRIPTION

The invention will now be taught using various exemplary embodiments.Although the embodiments are described in detail, it will be appreciatedthat the invention is not limited to just these embodiments, but has ascope that is significantly broader. The appended claims should beconsulted to determine the true scope of the invention.

In other words, embodiments of a surface cleaning and modifying methodand surface cleaning and modifying apparatus according to the presentinvention are hereinafter described, but the invention is not limited tothose embodiments.

Plastic optical components to which the surface cleaning and modifyingmethod of the invention is applicable involve a plastic spectacle lens,a plastic lens constituting an optical system in various types ofcameras, a cover glass used as a protective cover for a display deviceof portable equipment and so forth. Examples of the material includediethylene glycol bisallyl carbonate (CR-39) resin, polyurethane resin,thiourethane resin, polycarbonate resin, acrylic resin and othermaterial.

Unlike inorganic glass, a plastic optical component is easily scratcheddue to its softness. Especially for a spectacle lens, formation ofhard-coating is essential surface treatment so as to improve thehardness of the lens surface and tight connection with an evaporatedcoating and provide colorability. Described below is an example of aplastic lens as a plastic optical component.

In a hard-coating forming step, a film of hard-coating liquid is formedon the surface of the plastic lens by dipping the plastic lens in thehard-coating liquid containing fine particles of metal oxide, binders,catalysts and others, or by spin-coating or other coating method.Subsequently, the hard-coating film is hardened by heating for two tothree hours at 120 to 140 degrees Celsius to form a hard-coating.Formation of the hard-coating is necessary on both sides of the plasticlens.

AS pretreatment before the hard-coating forming step, a cleaning stepfor cleaning the surface of the plastic lens to remove contaminant ordirt remaining on the surface of the plastic lens is indispensable.There are two methods for cleaning both sides of the plastic lens andforming the hard-coating thereon.

Flowcharts in FIG. 1 show two methods for cleaning both sides of theplastic lens and forming the hard-coating thereon. FIG. 1(a) is aflowchart of manufacturing steps in which cleaning and hard-coatingformation are carried out first on one side of a plastic lens andsubsequently on the other side, while FIG. 1(b) is a flowchart ofmanufacturing steps in which both sides of the plastic lens are cleanedand subsequently coated with hard-coatings at a time. The processingorder of a convex surface and a concave surface may be reversed.

In the surface cleaning and modifying method of the present invention, aself-cleaning step for cleaning an elastic abrasive body itself is addedto a scrub cleaning step for polishing and cleaning one side of theplastic lens with abrasive using the elastic abrasive body as describedabove.

FIG. 2 illustrates arrangements of lens cleaning equipment in a firstembodiment. FIG. 2(a) shows a condition during scrub cleaning, whileFIG. 2(b) shows a condition during self-cleaning. Lens cleaningequipment 100 includes surface cleaning and modifying apparatus 200 forscrub-cleaning one side of a plastic lens 1 with abrasive, watercleaning apparatus 300 for water-cleaning the side of the plastic lenspolished by the surface cleaning and modifying apparatus 200 to wash offthe abrasive and the like, and a drier 400 for drying the side of theplastic lens which is wet after cleaning. The surface cleaning andmodifying apparatus 200, the water cleaning apparatus 300 and the drier400 are disposed in series and their peripheries are veiled bybottom-attached cylindrical covers 201, 301 and 401, respectively. Anot-shown carrier for carrying the plastic lens in and out of theseapparatus is also provided.

Since the surface cleaning and modifying apparatus 200 and the watercleaning apparatus 300 have similar basic structures, only the structureof the surface cleaning and modifying apparatus 200 is herein described.FIG. 3 schematically illustrates the structure of the surface cleaningand modifying apparatus 200 in the first embodiment. The surfacecleaning and modifying apparatus 200 includes an optical componentholder 210 for holding and rotating the plastic lens 1 approximately ata center of the cylindrical cover 201 (see FIG. 2). The opticalcomponent holder 210 has a rotational shaft 211 and an absorption chuck212 positioned on the upper end of the rotational shaft 211. Therotational shaft 211 is hollow and rotated around a vertically extendingaxis by a not-shown driving motor. The absorption chuck 212 holds theplastic lens 1 by absorption and communicates with the hollow portion ofthe rotational shaft 211. The not-shown carrier carries the plastic lens1 in so as to bring the lower surface of the plastic lens 1 into contactwith the absorption chuck 212 while aligning a geometrical center of theround-shaped plastic lens 1 with a center of the rotational shaft 211.

A not-shown vacuum piping is connected to the hollow portion of therotational shaft 211, by which piping the absorption chuck 212 isevacuated after the lower surface of the plastic lens 1 comes intocontact with the absorption chuck 212 such that the absorption chuck 212can hold the lower surface of the plastic lens 1 by absorption. An uppersurface of the plastic lens 1 thus held is a convex surface 2 or aconcave surface 3 in need of cleaning and modifying. Described below isan example of cleaning the convex surface 2, and the same method isapplicable to the concave surface 3. Additionally, a pressing member 220in the shape of a round bar, for example, is disposed within the cover201 away from the optical component holder 210 and close to the cover201 (see FIG. 2). The pressing member 220 will be described later.

An elastic abrasive body 230 in a cylindrical shape having a short axisis supported by an abrasive body holder 240 such that the peripheralsurface of the elastic abrasive body 230 is rotatable around ahorizontal axis. The abrasive body holder 240 has a vertically standingsupport 241 which is disposed outside the cover 201. The support 241 isrotated clockwise and anticlockwise by a driving force of an operationsection 250, and is also capable of rising and descending in a fixedrange. A base end of a support arm 242 as a cantilevered boom extendinghorizontally is securely attached to the upper end of the support 241. Ahorizontal bearing 243 is fixed to the tip of the support arm 242. Oneend of a flex shaft 244 is supported by the bearing 243, and the end ofthe flex shaft 244 passing through the bearing 243 is secured to ahollow portion positioned at the center of the elastic abrasive body230. The other end of the flex shaft 244 is directly connected with arotational shaft of a motor 245. The rotation of the motor 245 istransmitted through the flex shaft 244 to the elastic abrasive body 230.Thus, the elastic abrasive body 230 is so supported by the abrasive bodyholder 240 as to be rotatable around the horizontal rotation axis. Theelastic abrasive body 230 also circles with the rotation of the support241 rotated by the operation section 250 and moves upward and downwardwith the rising and descending of the support 241.

The rotations and the rising and descending motions of the support 241by the driving of the operation section 250 are sequentially controlled,for example. The operation section 250 performs the following actions: acleaning action for lowering the elastic abrasive body 230 positionedapproximately above the center of the plastic lens 1 which is supportedand rotated by the optical component holder 210 to press the rotatingelastic abrasive body 230 against the rotating plastic lens 1 and deformthe elastic abrasive body 230, and subsequently shifting the rotatingelastic abrasive body 230 from the center to the edge of the plasticlens 1 at a predetermined speed; an action for raising the elasticabrasive body 230 which has reached the edge of the plastic lens 1 toseparate the elastic abrasive body 230 from the plastic lens 1; aself-cleaning action for shifting the elastic abrasive body 230positioned above the edge of the plastic lens 1 in a horizontaldirection to press the elastic abrasive body 230 against the pressingmember 220; and an action for shifting the elastic abrasive body 230,which has been pressed against the pressing member 220, to a positionabove the center of the next plastic lens 1 after the plastic lens 1thus cleaned is transferred from the optical component holder 210 to thenext step by the carrier and the next plastic lens 1 is attached to theoptical component holder 210. These actions are repeated.

The elastic abrasive body 230 may be a liquid-permeable abrasive spongewhich is made from PVA, urethane, PP or other material. A sponge madefrom PVA, urethane, PP or other material in which abrasive is dispersedduring shaping may also be used. The elastic abrasive body 230 in whichabrasive is dispersed may be employed for both of the surface cleaningand modifying apparatus 200 and the water cleaning apparatus 300. PVA isa hard material when dried, and softens like a sponge when wet.

The shape of the elastic abrasive body 230 is generally a cylindricalshape having a short axis. However, the shape may be dome-shaped, forexample, and is not specifically limited. The peripheral surface of theelastic abrasive body 230 used for polishing the plastic lens 1 may haveconcaves and convexes or may be smooth.

A liquid outlet 260 is secured on the horizontal arm 242 of the abrasivebody holder 240 above the elastic abrasive body 230 to deliver liquid tothe elastic abrasive body 230 from above. The liquid outlet 260 is sodesigned as to supply liquid to the elastic abrasive body 230 all thetime even when the elastic abrasive body 230 is shifted. The elasticabrasive body 230 is formed by a liquid-permeable sponge, and the liquidsupplied to the elastic abrasive body 230 passes through the elasticabrasive body 230 to reach the surface of the plastic lens 1. While theelastic abrasive body 230 is being pressed against the convex surface 2of the plastic lens 1, the liquid having passed through the elasticabrasive body 230 enters between the elastic abrasive body 230 and theconvex surface 2 of the plastic lens 1.

The scrub cleaning step is performed while the elastic abrasive body 230pressed against the plastic lens 1 is moving from the center to the edgeof the plastic lens 1, and the self-cleaning step is performed while theelastic abrasive body 230 is being pressed against the pressing member220. During these actions, the elastic abrasive body 230 keeps rotating.When the plastic lens 1 is successively cleaned, the scrub cleaning stepand the self-cleaning step are alternately conducted.

When the plastic lens 1 is not carried in during operation, the rotationof the elastic abrasive body 230 is stopped with the elastic abrasivebody 230 pressed against the pressing member 220, along with aninterruption of liquid supply. However, the elastic abrasive body 230 isrotated and the liquid is supplied at predetermined time intervals toperiodically conduct the self-cleaning step.

FIG. 4 is a conceptual view showing a condition during the self-cleaningstep. The rotating elastic abrasive body 230 is pressed against theround-bar-shaped pressing member 220, thereby deforming the peripheralsurface of the elastic abrasive body 230. Liquid L is poured from theliquid outlet 260 to the upper surface of the deformed elastic abrasivebody 230. The liquid L is water when the elastic abrasive body 230contains abrasive dispersed therein, or slurry which contains abrasivedispersed in liquid such as water when the elastic abrasive body 230does not include abrasive. The foregoing statements do not rule out thepossibility of abrasive being in the liquid and also in the elasticbody.

The abrasive employed herein may be any type available on the market forabrasive purpose, including metal oxide such as Al₂O₃, CeO₂, SiO₂, Sio,ZrO₂ and Cr₂O₃, or carbide such as sic and C. For the plastic lens 1,abrasive made of Al₂O₃ is preferably used. The particle diameter andconfiguration of the abrasive is arbitrarily determined in accordancewith the material, shape and objects adhering to the surface, or adesired surface roughness of the plastic optical component to bepolished. Slurry which contains abrasive dispersed in water is used soas to diffuse frictional heat caused between the elastic abrasive lens230 and the plastic lens 1 and improve fitness with the shape of theconvex surface 2.

As described above, the self-cleaning step is a process in which theelastic abrasive body 230 itself is cleaned by supplying liquid whiledeforming the elastic abrasive body 230 to remove dirt therefrom. Byproviding the self-cleaning step, dirt and contaminant adhering to theelastic abrasive body 230 are removed and their re-adhesion to theplastic lens 1 is prevented. Thus, the possibility of dirt adhering toand large scratch formed on the plastic lens 1 is eliminated. When theplastic lens 1 is cleaned with the elastic abrasive body 230 which isdried after a long non-cleaning period, the plastic lens 1 may belargely scratched. Thus, a function for preventing desiccation of theelastic abrasive body 230 and resultant large scratch formed on theplastic lens 1 is also provided. When the plastic lens 1 is not carriedin for more than a predetermined time period during operation, theself-cleaning is compulsively performed at predetermined time intervalsto securely prevent the elastic abrasive body 230 from being dried.

Generally, the elastic abrasive body 230 is deformed by pressing theround-bar shaped or cylindrical pressing member 220 and the elasticabrasive body 230 against each other in the self-cleaning step. Thepressing member 220 is required to have a size sufficient to contact theentire peripheral surface of the elastic abrasive body 230 used forcleaning when the elastic abrasive body 230 is rotated. Thecross-sectional shape of the pressing member 220 may be either round orrectangular, but is preferably round when the pressing member 220 iseasy to be scratched by the material of the elastic abrasive body 230.

The material employed for the pressing member 220 may include iron,stainless steel, plastic, ceramic and other materials, but its cleaningeffect will be lowered if the material is too soft to withstand thepressing by the elastic abrasive body 230. Additionally, a materialwhich may reversely contaminate the elastic abrasive body 230 by rustingor bleeding out cannot be used. The pressing member 220 is preferablydisposed in such a position that the portion of the pressing member 220contacting with the elastic abrasive body 230 lies parallel to therotation axis of the elastic abrasive body 230 when the abrasive bodyholder 240 is circled to separate the elastic abrasive body 230 awayfrom the plastic lens 1, thereby bringing the pressing member 220 intocontact with the peripheral surface of the elastic abrasive body 230uniformly.

The scrub cleaning step performed by the surface cleaning and modifyingapparatus 200 is now described. The not-shown carrier transfers theplastic lens 1 from a stand-by position to the surface cleaning andmodifying apparatus 200. The absorption chuck 212 of the opticalcomponent holder 210 holds the concave surface 3 of the plastic lens 1by absorption with the convex surface 2 on the upper side. The opticalcomponent holder 210 rotates the plastic lens 1 at 500 to 1,000 rpm. Theoperation section 250 circles the support 241 to dispose the elasticabrasive body 230 above the plastic lens 1 while the abrasive bodyholder 240 rotates the elastic abrasive body 230 at 30 to 500 rpm.

Subsequently, the operation section 250 lowers the elastic abrasive body230 to press the elastic abrasive body 230 against the center of theplastic lens 1. Slurry containing abrasive is supplied from the liquidoutlet 260 to the upper-side peripheral surface of the elastic abrasivebody 230. Dirt on the plastic lens 1 is not sufficiently removed whenthe supply amount of slurry is too small, while slurry may scatteroutside the cover 201 due to the rotations of the plastic lens 1 and theelastic abrasive body 230 when the supply amount of slurry is too large.

It is thus necessary to determine the amount of slurry appropriately.When the amount of slurry supplied during self-cleaning is sufficientfor scrub cleaning, replenishment of slurry during scrub cleaning is notneeded. The rotating elastic abrasive body 230 pressed against theplastic lens 1 is shifted from the center to the edge of the plasticlens 1 to polish the convex surface 2 of the plastic lens 1 withabrasive. By providing the scrub cleaning step in which the plastic lens1 is rotated and the rotating elastic abrasive body 230 is pressedagainst the plastic lens 1 while supplying slurry containing abrasivebetween the elastic abrasive body 230 and the surface of the plasticlens 1 so as to movably clean the plastic lens 1, dirt or contaminant onthe entire convex surface 2 of the plastic lens 1 can be scrubbed offwith abrasive and also a non-uniform surface created during shaping ordue to degradation after shaping or by other cause can be removed.

After the scrub cleaning step, the self-cleaning step is performed inthe following manner. The operation section 250 circles the support 241to shift the elastic abrasive body 230 from the shaped lens body 2 tothe pressing member 220. The abrasive body holder 240 rotates theelastic abrasive body 230 at 30 to 500 rpm while pressing the elasticabrasive body 230 against the pressing member 220. In this condition,the liquid supply member 260 supplies slurry containing abrasive to theelastic abrasive body 230 along with the deformation of the elasticabrasive body 230 caused by the pressing member 220 so as to conduct theself-cleaning step.

The time required for the self-cleaning differs depending on the levelof dirt on the elastic abrasive body 230. However, it is desirable tofinish this process with the least possible delay in the cleaning timeschedule, generally only in several seconds during carrying-in of theplastic lens 1. Additionally, the elastic abrasive body 230 may scratchthe plastic lens 1 if the elastic abrasive body 230 is dried before thestart of cleaning or after a long period of stop. Thus, it is preferableto moisten and soften the elastic abrasive body 230 by the self-cleaningstep in such a case.

In the surface cleaning and modifying process where the scrub cleaningstep and the self-cleaning step are alternated, since the scrub cleaningstep is performed using the elastic abrasive body 230 which is alwayscleaned by the self-cleaning step conducted between the scrub cleaningsteps, the plastic lens 1 can be cleaned without leaving dirt or largescratch thereon.

When the elastic abrasive body 230 in which abrasive is dispersed isemployed, the scrub cleaning step and the self-cleaning step areconducted under the same conditions as described above except that wateris used in lieu of slurry.

Next, a water cleaning process performed by the water cleaning apparatus300 is described. The scrub cleaning step and the self-cleaning step aresimilarly involved in the water cleaning process. For example, thenot-shown carrier transfers the plastic lens 1, which has been cleanedby the surface cleaning and modifying apparatus 200 in the surfacecleaning and modifying process, to the water cleaning apparatus 300. Theabsorption chuck 212 of the optical component holder 210 holds the lowersurface of the plastic lens 1 by absorption with the convex surface 2 onthe upper side.

The optical component holder 210 rotates the plastic lens 1 at 500 to1,000 rpm. The operation section 250 shifts the elastic abrasive body230 to a position above the plastic lens 1, while the abrasive bodyholder 240 rotates the elastic abrasive body 230 at 30 to 500 rpm.Subsequently, the operation section 250 lowers the elastic abrasive body230 to press the elastic abrasive body 230 against the center of theplastic lens 1. Water is supplied from the liquid outlet 260 to theupper peripheral surface of the elastic abrasive body 230. Pure water ispreferably used for rinsing off. The elastic abrasive body 230 pressedagainst the plastic lens 1 is shifted from the center to the edge of theplastic lens 1 to scrub the entire convex surface 2 of the plastic lens1 using the elastic abrasive body 230.

By providing the water cleaning step in which the plastic lens 1 isrotated and the rotating elastic abrasive body 230 is pressed againstthe plastic lens 1 while supplying water between the surface of theplastic lens 1 and the elastic abrasive body 230 so as to clean theplastic lens 1 with water, abrasive and the like remaining on the convexsurface 2 of the plastic lens 1 can be scrubbed off.

After the cleaning process, the elastic abrasive body 230 is shiftedfrom the plastic lens 1 to the pressing member 220. The elastic abrasivebody 230 rotating at 30 to 500 rpm is pressed against the pressingmember 220 while supplying water to the elastic abrasive body 230 so asto perform the self-cleaning step. The elastic abrasive body 230 mayscratch the plastic lens 1 if the elastic abrasive body 230 is driedbefore the start of cleaning or after a long period of stop. Thus, it ispreferable to moisten and soften the elastic abrasive body 230 by theself-cleaning step in such a case.

Also in the water cleaning process where the scrub cleaning and theself-cleaning are alternated, since the water cleaning is performedusing the elastic abrasive body 230 which is always cleaned by theself-cleaning step conducted between the cleaning steps, the plasticlens 1 can be cleaned without leaving dirt or any large scratch thereon.

In the example described above, cleaning of the plastic lens 1 and theself-cleaning are performed by shifting the elastic abrasive body 230.However, the scrub cleaning of a plastic optical component and theself-cleaning can be similarly conducted by shifting the opticalcomponent holder 210 for holding the plastic lens 1 and the pressingmember 220 with the elastic abrasive body 230 fixed to press thepressing member 220 against the elastic abrasive body 230.

Additionally, in the above description, the liquid supply member isshifted together with the elastic abrasive body to supply the sameliquid in both of the scrub cleaning step and the self-cleaning step.However, a liquid supply member may be provided in each of the scrubcleaning step and the self-cleaning step so as to supply differentliquid in each step.

Described now is the drier 400. The drier 400 includes the opticalcomponent holder 210 for holding and rotating the plastic lens 1 and avolatile liquid supply member 261 for dropping volatile liquid such asisopropyl alcohol approximately onto the center of the plastic lens 1(see FIG. 2).

In a drying process performed by the drier 400, the not-shown carriertransfers the plastic lens 1 from the water cleaning apparatus 300 tothe drier 400 after the water cleaning process. The absorption chuck 212of the optical component holder 210 holds the concave surface 3 of theplastic lens 1 by absorption with the convex surface 2 on the upperside. The optical component holder 210 rotates the plastic lens 1 at 200to 3,000 rpm, preferably 800 to 2,000 rpm. Volatile liquid is dropped onthe rotating plastic lens 1. The dropped volatile liquid is spread outby a centrifugal force. Consequently, water existing on the convexsurface 2 is replaced by a thin film of the volatile liquid, and theconvex surface 2 is dried by volatilization of the thin film of thevolatile liquid.

Additionally, in the drying process, heated water may be employed asvolatile liquid. In this case, the drier preferably includes a dry airsupply member for supplying dry air to the plastic lens 1 from above, anoutlet provided at a bottom wall or a lower portion of a side wall ofthe cover 401 for discharging the dry air supplied from the dry airsupply member, and a hot water supply member for supplying heated waterat temperatures ranging from 30 to 100° C., preferably from 50 to 70° C.in lieu of the volatile liquid supply member.

In a hot water supply step, hot water is dropped from the hot watersupply member onto the convex surface 2 of the plastic lens 1 while theoptical component holder 210 rotates the plastic lens 1 at revolution of50 to 300 rpm, preferably at 100 to 200 rpm. The dropped hot water isspread out by a centrifugal force, forming a uniform thin film on theconvex surface 2 of the plastic lens 1. Subsequently, the dry air supplymember supplies dry air to the surface of the plastic lens 1 while theoptical component holder 210 rotates the plastic lens 1 at highrotational speed of 200 to 3,000 rpm, preferably 800 to 2,000 rpm todrain water. As a result, the film of hot water formed on the convexsurface 2 of the plastic lens 1 is evaporated and the plastic lens 1 isthus dried.

After the convex surface 2 of the plastic lens 1 is thus cleaned andmodified by the surface cleaning and modifying apparatus 200, the watercleaning apparatus 300 and the drier 400, hard-coating liquid is appliedto the convex surface 2 by spin-coating, for example. Then, the convexsurface 2 is burnt to form a hard-coating thereon. Similarly, after theconcave surface 3 of the plastic lens 1 whose convex surface 2 has beencoated with the hard-coating is cleaned and modified by the surfacecleaning and modifying apparatus 200, the water cleaning apparatus 300and the drier 400, hard-coating liquid is applied to the concave surface3 by spin-coating, for example, and subsequently the concave surface 3is burnt to form a hard-coating thereon. Thus, the hard-coating is nowformed on both sides of the plastic lens 1.

As an alternative method, a hard-coating may be formed simultaneously onboth sides of the plastic lens 1 by employing a dipping method in which:after the convex surface 2 of the plastic lens 1 and subsequently theconcave surface 3 on the opposite side are cleaned and modified by thesurface cleaning and modifying apparatus 200, water cleaning apparatus300 and the drier 400, hard-coating liquid is applied to the plasticlens 1 by dipping the plastic lens 1 into hard-coating liquid.

When a hard-coating is simultaneously formed on both sides of theplastic lens 1 by the dipping method, it is possible to successivelyclean the convex surface 2 and the concave surface 3 by using lenscleaning equipment of a second embodiment illustrated in FIGS. 5 and 6.

Lens cleaning equipment 101 shown in FIG. 5 includes a rotary carrier500 capable of carrying and processing four plastic lenses 1simultaneously. The rotary carrier simultaneously carries four plasticlenses 1 which are supplied to A, B, C, D, E and again A in FIG. 5 inthis order to process the plastic lenses 1. Four plastic lenses 1 aresupplied to a supply and removal section A with the convex surfaces 2 onthe upper side. A convex surface cleaning and modifying section Bincludes four surface cleaning and modifying apparatus so as tosimultaneously clean and modify the convex surfaces 2 of the suppliedfour plastic lenses 1. At a shower-cleaning and turning-over section C,water cleaning is performed by pouring pressurized water onto the convexsurfaces 2 of the four plastic lenses 1 from above, and the plasticlenses 1 thus cleaned are turned over to dispose the concave surfaces 3on the upper side.

A concave surface cleaning and modifying section D includes four surfacecleaning and modifying apparatus so as to simultaneously clean andmodify the concave surfaces 3 of the four plastic lenses 1 which havebeen turned over. At a shower cleaning section E, water cleaning isperformed by pouring pressurized water onto the concave surfaces 3 ofthe four plastic lenses 1 from above. After the cleaning and modifyingprocess is completed on both sides of the plastic lenses 1, the fourplastic lenses 1 are removed at the supply and removal section A.

A rather facilitated method of shower cleaning is employed for the watercleaning, since a dipping step is practiced as pretreatment for thehard-coating formation after both surfaces are cleaned and modified bythe lens cleaning equipment 101. However, water scrub-cleaning using theelastic abrasive body as described above may be carried out instead ofshower cleaning.

FIGS. 6(a), 6(b), and 6(c) together schematically illustrate a structureof surface cleaning and modifying apparatus provided at the convexsurface cleaning and modifying section B of the lens cleaning equipment101 in a second embodiment. The surface cleaning and modifying apparatusprovided at the concave surface cleaning and modifying section D has thesame structure. FIG. 6(a) shows dispositions of respective components ina condition where scrub cleaning and self-cleaning are not performed,FIG. 6(b) shows a condition during scrub cleaning, and FIG. 6(c) shows acondition during self-cleaning.

Surface cleaning and modifying apparatus 202 in this embodimentincludes: an elastic abrasive body 231; the optical component holder 210for holding the lower surface of the plastic lens 1 and rotating theplastic lens 1; a pressing member 221; and a not-shown operation sectionfor driving and controlling the optical component holder 210 and thepressing member 221. The elastic abrasive body 231 which is verticallydisposed is cylindrical in shape having a dome-shaped lower surface. Anupper end surface of the elastic abrasive body 231 is integrallyconnected with a lower surface of a disc-shaped elastic abrasive bodyfixing member 232 which is made from a hard material and hasapproximately the same diameter as that of the elastic abrasive body231. The elastic abrasive body 231 is supported by a not-shown abrasivebody holder in such a manner as to be rotatable around a vertical centeraxis of the elastic abrasive body 231. A through hole 233 is provided atthe center of the elastic abrasive body fixing member 232. The outsidediameter of the elastic abrasive body 231 is larger than the radius ofthe plastic lens 1, and is rather close to the diameter of the plasticlens 1.

The elastic abrasive body 231 may be a liquid-permeable abrasive spongewhich is made from PVA, urethane, PP or other material. Alternatively, asponge made from PVA, urethane, PP or other material in which abrasiveis dispersed during shaping may be used.

Though not shown, also provided is a liquid supply member for supplyingliquid to the through hole 233 positioned at the center of the elasticabrasive body fixing member 232. The liquid supplied to the through hole233 passes through the elastic abrasive body 231 by its gravity andflows out mainly from its dome-shaped lower surface.

The optical component holder 210 in this embodiment is similar to thatin the above-described embodiment, and includes the rotational shaft 211and the absorption chuck 212 positioned at the upper end of therotational shaft 211. The rotational shaft 211 is hollow and rotatedaround a vertically extending axis in a direction opposite to therotation direction of the elastic abrasive body 231 by a not-showndriving motor. The absorption chuck 212 holds the plastic lens 1 byabsorption and communicates with the hollow portion of the rotationalshaft 211. The optical component holder 210 is movable upward anddownward, and its position is controlled by the operation section. Therotation center of the optical component holder 210 in the verticaldirection and the rotation center of the elastic abrasive body 231 inthe vertical direction deviate from each other so as to preventinsufficient polishing at the rotation center.

The pressing member 221 in the shape of flat plate is disposed in ahorizontal direction. The front end of the pressing member 211 on theelastic abrasive body side is tapered with the upper side in thisportion cut off. The pressing member 221 is movable in the horizontaldirection, and its position is controlled by the operation section. Thepressing member 221 is disposed in such a position as to carry theentire lower surface of the elastic abrasive body 231 when the pressingmember 221 is moved to the most advanced position. The upper surface ofthe pressing member 221 is positioned slightly above the tip of thelower surface of the elastic abrasive body 231. The material of thepressing member 221 is the same as that of the pressing member 220described above.

A surface cleaning and modifying method using the surface cleaning andmodifying apparatus 202 as mentioned is now described. The rotarycarrier 500 carries the plastic lens 1 in the surface cleaning andmodifying apparatus 202 such that the geometrical center of the plasticlens 1 is aligned with the center of the rotational shaft 211 of theoptical component holder 210 and that the concave surface 3 of theplastic lens 1 contacts the absorption chuck 212. A not-shown vacuumpiping is connected with the hollow portion of the rotational shaft 211,by which piping the absorption chuck 212 is evacuated after the lowersurface of the plastic lens 1 comes into contact with the absorptionchuck 212 so that the absorption chuck 212 can hold the concave surface3 of the plastic lens 1 by absorption.

In the scrub cleaning step, the optical component holder 210 which holdsthe plastic lens 1 by absorption and rotates the plastic lens 1 atrevolution of 50 to 300 rpm, preferably 100 to 200 rpm is raised by thecontrol of the operation section to press the convex surface 2 of theplastic lens 1 against the lower surface of the elastic abrasive body231 rotating at 50 to 100 rpm as illustrated in FIG. 6(b). The lowersurface of the elastic abrasive body 231 contacts at least a regioncorresponding to the radius of the plastic lens 1. As a result, theentire area of the rotating plastic lens 1 can be polished withoutshifting the elastic abrasive body 231.

During the scrub cleaning step, slurry containing abrasive as liquid Lis supplied to the through hole 233 from a not-shown liquid supplymember. The scrub cleaning continues for several seconds to about oneminute, generally for about twenty seconds.

By providing the scrub cleaning step in which the plastic lens 1 isrotated and the rotating elastic abrasive body 231 is pressed againstthe plastic lens 1 while supplying slurry containing abrasive betweenthe elastic abrasive body 231 and the surface of the plastic lens 1 soas to polish the plastic lens 1 with abrasive, dirt or contaminant onthe entire convex surface 2 of the plastic lens 1 can be scrubbed offwith abrasive and also a non-uniform surface created during shaping ordue to degradation after shaping or by other cause can be removed.

Next, in the self-cleaning step, the optical component holder 210 islowered by the control of the operation section while continuing therotation of the elastic abrasive body 231 and the supply of the liquid Lfrom the liquid supply member after the scrub cleaning as illustrated inFIG. 6(c). Then, the pressing member 221 is advanced while pressingagainst the tip of the dome-shaped portion of the elastic abrasive body231 used for polishing, thereby deforming that portion carried on thepressing member 221. By providing the cleaning step in which the portionof the rotating elastic abrasive body 231 used for polishing is pressedagainst the pressing member 221 into deformation while supplying theliquid L to the elastic abrasive body 231 so as to clean the portion ofthe elastic body 231 used for polishing, contaminant or dirt adhering tothe elastic abrasive body 231 can be cleaned off, preventing re-adhesionof the dirt or contaminant to the plastic lens 1 to be cleaned next.

During the self-cleaning step, the scrub-cleaned plastic lens 1 istransferred to the next shower-cleaning and turning-over section C bythe rotary carrier 500, and the plastic lens 1 supplied at the supplyand removal section A is carried in the convex surface cleaning andmodifying section B. After the self-cleaning step, the operation sectionretreats the pressing member 221 to its original position, and thenraises the optical component holder 210 holding the next plastic lens 1by absorption to perform the scrub cleaning step.

In the above example, slurry which contains abrasive dispersed in liquidsuch as water is employed as the liquid L. However, water may be used asthe liquid L when the elastic abrasive body 231 contains abrasivedispersed therein, in which case the scrub cleaning and theself-cleaning can be performed exactly in the same manner as above.

In the surface cleaning and modifying process where the scrub cleaningstep and the self-cleaning step are alternated, since the cleaning isperformed with the elastic abrasive body 231 which is always cleaned bythe self-cleaning step conducted between the scrub cleaning steps, theplastic lens 1 can be cleaned without leaving dirt or large scratchthereon.

In the above example, the scrub cleaning step and the self-cleaning stepare conducted by raising and lowering the optical component holder andshifting the pressing member in the horizontal direction by the controlof the operation section. However, these steps can be similarlypracticed by shifting the elastic abrasive body with the opticalcomponent holder and the pressing member fixed. Additionally, theflat-plate-shaped pressing member is employed herein as an example, buta bar-shaped type which can similarly deform the lower surface of theelastic abrasive body may be used.

In the above example, hard-coating is formed as surface treatment afterthe surface cleaning and modifying step, but other surface treatmentsuch as formation of a primer layer may be given.

Many further variations to the above-identified embodiments are possiblewithout departing from the scope and spirit of the invention.

1. A surface cleaning and modifying method, comprising: scrub cleaning a plastic optical component, including: rotating the plastic optical component, pressing a rotating elastic abrasive body against a surface of said plastic optical component, and during the pressing, supplying a liquid between the surface of said plastic optical component and said elastic abrasive body, wherein the liquid is a slurry comprising dispersed abrasive; and self-cleaning said elastic abrasive body, including: deforming said elastic abrasive body, and during the deforming, supplying a liquid, to said elastic abrasive body, the liquid being a slurry comprising dispersed abrasive.
 2. The surface cleaning and modifying method as set forth in claim 1, wherein said self-cleaning further comprises placing said elastic abrasive body and a pressing member in contact to deform said elastic abrasive body.
 3. The surface cleaning and modifying method as set forth in claim 1, further comprising alternately performing said scrub cleaning and said self-cleaning.
 4. A surface cleaning and modifying method, comprising: scrub cleaning a plastic optical component, including: rotating the plastic optical component, pressing a rotating elastic abrasive body against a surface of said plastic optical component, the elastic abrasive body comprising dispersed abrasive, and during the pressing, supplying a liquid comprising water between the surface of said plastic optical component and said elastic abrasive body; and self-cleaning said elastic abrasive body, including: deforming said elastic abrasive body, and during the deforming, supplying a liquid comprising water to said elastic abrasive body.
 5. The surface cleaning and modifying method as set forth in claim 4, wherein said self-cleaning further comprises placing said elastic abrasive body and a pressing member in contact to deform said elastic abrasive body.
 6. The surface cleaning and modifying method as set forth in claim 4, further comprising alternately performing said scrub cleaning and said self-cleaning.
 7. A surface cleaning and modifying apparatus, comprising: an optical component holder holding and rotating a plastic optical component; a pressing member separate from said optical component holder; an abrasive body holder holding and rotating an elastic abrasive body; an operation section operating one or more of said optical component holder and said abrasive body holder so as to perform operations, including: a cleaning action of pressing said elastic abrasive body against said plastic optical component, and a self-cleaning action of placing said elastic abrasive body in contact with said pressing member; and a liquid supply member for supplying liquid to said elastic abrasive body during said cleaning action and said self-cleaning action.
 8. The surface cleaning and modifying apparatus as set forth in claim 7, wherein said operation section alternately conducts said cleaning action and said self-cleaning action.
 9. The surface cleaning and modifying apparatus as set forth in claim 7, wherein said liquid is a slurry comprising dispersed abrasive.
 10. The surface cleaning and modifying apparatus as set forth in claim 7, wherein said elastic abrasive body comprises dispersed abrasive.
 11. The surface cleaning and modifying apparatus as set forth in claim 10, wherein said liquid comprises water. 